Electric stove



A C. HARRINGTON.

ELECTRiC STOVE.

APPLICATioN HLED MAY'za. 1920.

1,388 ,1 l l v Patented A110'. l16, 1921.

A TTOH/VEYS adjusting means in connection wit PATENT OFFICE.

.ALLAN C. HABRING'TON, 0F CHICAGO, ILLINOIS.

ELECTRIC STO'VE.

Specification of Letters Patent. Patented Allg. 16, 1921.

Application illed Hay 28, 1920. 'Serial No. 384,884. f

following is a full, clear, and exact descrip-- tion. This inventionrelates to electric stoves, and has particular reference to one in Whlchthermostatic control of the generated heat is provided'.

An objectof the invention is to provide asimple, compact electric stovein which the generated heat is under a much finer degree of controlthanis usually the case.

Another object is -to provide 'a theremostatic device in which theresponse of the thermostatic element to the generated heat is uniformand sensitive to a very high deree.

Still another object is to provide a means whereby the .heater circuitmay be opened and closed at predetermined temperatures by the use of asimple and readil operable li the thermostat.

The invention in general comprises a receptacle having double wallsbetween -which there is a vacuum and which contains an electricalheating element. Also located Within the. receptacle is a therm'ostaticydel vice in the form of a coiled spring o f' heatresponsive material.`rI his spring is connected to suitable linkage, whereby a leverI armconnected thereto on the exterior of `the receptacle is moved either toindicate the v temperature Within .the receptacle or to move al switchor to perform some other function. In order to insure that the expansionand contraction of this coil spring may be very uniform and result in anincreased sensitivity of the device, Iit is provided that at 'frequentintervals throughout its length the coiled spring is confined on bothsides by guiding elements, so that when a tendency exists to expandunder heat, the general coni figuration ofthe spring when coiled i'smaintained and the expansion takesv place substantially entirely alongthe length .of the spring. In this way an increased movement of thespring is obtained which is effective to move the indicator or otherdevice on the exterior o f .the receptacle. f

This thermostatic element is connected by suitable'means to a rotatableelement on the exterior of the receptacle. Adjacent this rotatableelement is an electric circuitcloser. The circuit closer is connected tothevrotatable element b means of an adjustable link, the position owhich may be varied at will, to determine the amount of movement of therotatable element required before its movement results in either theopening or closing of the circuit closer.

The inventiony is illustrated in the drawing, of which- Figure l is alongitudinal section of the stove taken on the line l-l of Fig. 2;

Fig. 2 is a plan view of the stove; Fig. 3 is an enlarged plan view ofthe top of the circuit-controlling means locatedv on the top of thestove;

Fig. 4 isa vertical section taken on the line 4-4 of Fig. 3;

Fig. 5 is a horizontal line 5--5 of Fig. .4; and

Fig. 6 is a detail view of the circuit-closer terminals. kAs'illustrated in the drawings, the invention comprises areoeptaclehaving innerand outer walls 1 and 2 and a tight-fitting cover,which also has inner and outer walls 3 and 4. These walls may be made ofany suitable material, such as glass, porcelain or metal, and may bejoined in an air-tight manner by any method known in thearts. Betweensection taken on the v placed therein to more effectively prevent theradiation and conduction of heat from the interior of the receptacle tothe exterior.

Positioned within the receptacle, preferably on the bottom, is a heaterelement, represented by the numeral 5. This element 5 is onlydiagramm-atically represented, since it may be of any w'ell-knovvn'andYsuitable form. A pipe 6 extends from this element 5 to the exterior ofthe receptacle and passes through the `space between the walls to theoutside and provides a passage for the circuit wires 7 and 8. Thesewires extend to a circuit closer to be hereinafter mentioned.

The cover of the receptacle is connected thereto in any suitable mannerand is provided on its inner surface with a casing 9,

which may be riveted or screwed thereto.

- which is of any Suitable man which is particularly responsive tochanges in temperature. This spring is wound in a flat spiral, the innerend of the spring being connected to a shaft 11 and the outer end beingconnected by a pin to aplate 12. The plate 12 is loosely mounted on theshaft 11. This shaft 11 is, at its lower end, fixed in the casing 9 andextends upwardly from the cas` ing 9 in a tube 13, which tube is sealedbetween the inner and outer walls of the cover so as to make it airtight. The upper end of the shaft 11 is fastened to a plate 14 on thetop of the cover. Along part of its periphery the plate 12 is providedwith teeth 15 which are adapted to mesh with a pinion 16 mounted on thelower end of shaft 17 and which extends upward from the casing 9 inatube 18, similar to the tube 13, and at its upper end is connected to aplate 19. The plate 19 is provided with a slot in the form of a sector20. A link 21 is loosely pivoted to the upper end of shaft 17 and,intermediate its length, is provided with an adjustable nut 22, aportion of which rides in the slot 20. This nut and slot arrange mentprovides means whereby lthe linl 21 may be adjusted in any position withrespect to the plate 19. The outer end of the link 2l is connected by aspring 22 with arm 23 of a circuit closer. This arm carries a contactplate 24 on its outer end, which is adapted to dispose itself betweenterminal springs 25 and 26 which are adapted to be connected to thecircuit wires 7 and 8.

It will be readily seen that by varying the position of the link 21 inthe slot 20 more or less movement will be required of the plate 19 underthe influence of the thermostatic element in order to either open orclose the switch, as the case may be,so that a rather wide degree ofadjustability is provided by this simple means.

As more clearly shown in Figs. 4 and 5, a plurality of to one face o thecasing 9. spaced apart at short intervals in lines which preferably, andas show n, extend at right angles to each other. The spring 10 isthreaded in a flat spiral form between these pins, which, therefore,confine the lateral movement of the spring at frequent intervalsthroughout its length. The spring, therefore, in expanding is preventedfrom moving laterally to any substantial degree and, therefore, tends tomove entirelyT 1n a longitudinal direction, thereby resulting in themost eflicient indication for any given change of temperature.

By the mechanism and the arrangement thereof above described it will bereadily seen that have provided asimple, compact stove, adapted to beheated electrically, in which heat-controlled device is located hese areand in ins 27 are securely fastenedl a simple and' easilyadjustableceptacle, a circuit closing arm, an element cooperating withsaid thermostatic device and movable in response to the movementthereof, said element cooperating with said circuit closing arm,connections between said element and said'circuit closing arm, and meansfor adjusting the relation of said connection with respect to thecircuit closing arm and said element.

2. An electric stove comprising a receptacle, a heating element withinvthe receptacle, a thermostatic device within the receptacle, a circuitclosing arm, a rotatable member operatively connected to saidthermostatic device and coperating with said circuit closing arm, an armonsaid rotatable member, said arm connected to said circuit closing arm,and means for adjusting the relation of said arm with respect to thecircuit closing arm and the rotatable member.

3. An electric stove comprising a receptac1e,.a heater element withinsaid receptacle, a thermostatic device within said receptacle, arotatable plate o eratively connected to said thermostatic evice andhaving a circular slot therein, a circuit closer, an arm connected tosaid rotatable plate and to said circuit closer, and means connected tosaid arm and o eratively associated with the slot to adjust tlie armwith respect to the rotatable plate and determine the character of theopening and closing of the circuit closer.

4. A thermostatic device comprising a coiled spring one end of which 1sfree to expand, means positioned at intervals throughout the length ofthe spring to conne its movement substantially to a direction coincidentwith its length.

5. A thermostatic, device comprising a coiled 'spring one end of whichis free to expand, a plurality of devices positioned along the length ofthe spring to confine the spring to its originalconguration when cold sothat when expanding under the inuence of heat this originalconfiguration is maintained and the expansion 1s substantially entirelylongitudinal.

GpA thermostatic device comprising a coiled spring one end of which 1sfre'e to expand, stationary devices positioned at incomprising a recep-ftervals throughout the length of the spring' to prevent lateral movementof the spring inexpanding. w

7. A thermostatc device comprising 'n coiled spring one endV of which 1slfree to expand, a plurality of pins positioned on both sides of saidspring at throughout its length, said pins adapted to confine themovementjof the springft a 1.0 direction parallel with itself.

8. A thermostatic device comprising a intervals .coiled spring one endof Ywhich is free` to expand, a'plural'ityof devices positioned alongthelength `ot said spring to conine it to a longitudinal movement, amovable plate fastened to the free a shaft operatively connected on thesaid movable plate, an arm on lthe outer end l of said shaft, and anindicating device con-` nected to and operated by saidarm.y

ALLAN c.- H'ARRINGTON.

15y end of the frame,v

